I am not who I used to be; a long time ago, I was a normal kid, who acted out a lot, and caused problems.

Actually no, I tell a lie; while I was normal, I quickly discovered I was really good at pranking people whom I thought deserved it.

I was the youngest of my family, constantly picked on, teased…and yet I knew something they didn't; I knew I was special. I was good at inventing dangerous things while nobody took me seriously.

All of that changed one Christmas; my family left me all on my own, leaving me behind in an empty house. The night before, my eldest brother deliberately scoffed down my pizza dinner and pretended to barf it all up - I was seething with fury. I threw myself on him, causing a flood of coke and drink all over the kitchen, and I was punished and taken to the attic room.

The next day, the house was empty.

I had made my family disappear.

For the next few days, I changed; I stopped being immature when I realised since nobody was around, I would have to fend for myself, cook my own meals, and keep the house tidy.

It was not long before I realised the house was vulnerable; on the very first night, I had fallen asleep watching movies, and I woke up and saw the shape of two men outside who were going to take advantage of my family's absence and rob our home, but I drove them off. But they didn't leave the area, and they realised I was on my own even when I had taken steps to trick them; I recognised the oldest man. He'd pretended to be a cop. He had asked my parents about the security arrangements; there's truly nothing more sly than a burglar disguising themselves up as a cop, telling people about a rising tide of burglaries in the area to get people to open up.

I got a good look at his face, and I was unsettled by his gold tooth.

I saw the same man again, after I'd accidentally stolen a toothbrush, of all things after being scared out of my wits by a neighbour rumoured to have committed the murder of his whole family. A van came out of a drive and just stopped inches from my face! One of the men in the van was the cop with the gold tooth; as I went on my way, wondering what that meant, I realised the van was following and I managed to hide myself just in time.

When the van left, I got home and realised the man with the gold tooth was one of the burglars. I tricked them both by faking a party with loud music.

The next day, they came around again, realised I lived at the house and I was alone, and they planned to break in again. I stopped them and set up dangerous traps and they got imprisoned.

My parents and siblings returned the next day, and over the next year, I became more mature and smarter.

But on the second Christmas, I accidentally got on the wrong flight to New York. I'd had another argument with my family after my eldest brother (again) got me in trouble with a tasteless prank, but I managed to get to the airport this time. Only I got sidetracked and I followed a man who was not my father onto a different plane, and I didn't learn the truth until I arrived in New York (my family would quickly discover their stupid Florida vacation was going to be a nightmare, even if I had been with them; it was pouring down buckets, and my cheapskate uncle had actually booked them into the seedy motel he and my Aunt Leslie had stayed in during their honeymoon).

I had a lot of fun in New York, at least for the first few days. I checked into one of the most expensive, lavish hotels in the city. But things turned dark when I learnt the burglars I'd met the year before were in the city as well. And they knew I was there. I was set to escape, to hide, when the concierge of the hotel exposed I had checked into a hotel room using my father's credit card.

I ran…right into the burglars. I learned they planned to steal the money accumulated by a toy store, which would then be donated to the children's hospital. That was a wonderful cause, and I was so touched by it.

I escaped, only to spend a scary night in New York before I set up traps in an abandoned brownstone and lured the burglars inside. Looking back, I know I had made the traps twice as brutal as before. I wanted them to pay, for stealing the money for helping children while they used it selfishly, and to vent my inner anger that they had dared escape in the first place, and to make me lose my temporary abode.

They were arrested…but I changed.

The second experience made me realise that nobody really cared about justice.

As I grew older, I continued working on my inventive skills, and I turned to helping others as best as I could when I moved to the East Coast while keeping in touch with my family. My life was normal and I never saw the burglars who'd haunted me like vengeful wraiths for years.

And then…I discovered I was dying of a terminal illness. I couldn't believe it, and I was shaken. I decided to make the whole world pay.

Oh, I don't mean that in the sense I decided to destroy the world. No, no, I wanted to play games with people who deserved to suffer. I went back to my childhood roots, setting up dangerous traps inside abandoned farms, factories, slaughterhouses, wherever. I targeted people who were like Marv and Harry, the burglars who'd come after me twice; I went for murderers who'd got off on technicalities, crooked lawyers and solicitors and attorneys, people who did not value life. In my mind, I wanted them to appreciate what they had.

I remade myself into the serial killer known as Jigsaw, but I saw myself as a teacher who taught everyone to appreciate life and to know when I let go. The trap with those two men who were involved in a love triangle with a vain, vapid little bitch queen from hell was and will always remain one of my favourite lessons, and I think it settled into their minds when they realised the girl didn't care about them, and they worked together when they quickly realised the truth and cut her in half with a saw.

I don't see myself as an unstable murderer; I am capable of empathy and kindness, and I do my best to be gentle and kind, but only towards those who deserve it. And I go for people who hurt others, especially little children.

And that is how I went from Kevin McCallister to John Kramer, aka Jigsaw.